1. Field of the Invention
The present invention relates generally to door hinges and, more specifically, to door hinge assemblies which provide pivotal guidance to the upper and lower doors of a refrigerator.
2. Brief Description of the Relevant Art
A wide variety of door hinge assemblies for mounting refrigerator doors to their associated cabinets are known to those skilled in the art. Typically, these assemblies provide an intermediate hinge pin support between upper and lower doors which operates as a bearing surface to support the load of the upper door and a vertically extending hinge pin to pivotally guide the upper and lower doors, keeping the doors in proper vertical alignment.
Just such a device is disclosed by U.S. Pat. No. 4,864,691 issued to Gidseg et al. The Gidseg patent discloses several hinge assemblies, including the use of a cabinet mounted hinge bracket intermediate the upper and lower doors which provides an opening for the vertically extending hinge pin. A pair of hinge members between the lower hinge of the upper door and the intermediate hinge cooperate to provide an access opening through which the hinge pin extends. The intermediate hinge bracket supports the weight of the upper door while a hinge pin guides the rotation of both the upper and lower doors, the weight of the lower door being borne by a lower hinge assembly. A similar hinge is shown by U.S. Pat. No. 4,774,740.
U.S. Pat. No. 4,084,291, issued to Crowe, discloses a cabinet mounted hinge bracket with a hinge pin extending therethrough. The upper end of the lower door and the lower end of the upper door provide inwardly directed thimbles which accept the vertically directed hinge pin. A cabinet mounted hinge bracket supports the weight of the upper door and provides guidance for the upper and lower doors as they pivot about the hinge pin, as is common in the art.
In all of the intermediate hinge assemblies known in the art, the intermediate hinge bracket supports the weight of the upper door and holds the hinge pin which pivotally guides the upper and lower doors. Since the intermediate hinge bracket is typically located in the area of the cabinet where there is limited structural strength, the frame in this area must be built up to support the weight of the upper door. Specifically, if the hinge is to be attached to the cabinet at the mullion strap, which is a preferred location, a frame capable of supporting the weight of the upper door must be introduced to the mullion region. Due to the limited strength at the mullion, it is common, as shown by the Gidseg and Crowe references, for the intermediate hinge bracket to be attached to the cabinet frame at a location which is close to, but not at, the mullion strap.
Increasing the size and strength of the frame in the area of the mullion to allow mounting of the intermediate hinge decreases the amount of thermal insulation that can be provided between the upper and lower compartments of the refrigerator. Furthermore, adding to the size of the frame also increases the weight of the refrigerator and complexity of assembly and, hence, the expense of the finished refrigerator.
Naturally, consumers increasingly demand lighter, more efficient and less expensive appliances. Furthermore, governmental regulations require ever-increasing levels of energy efficiency for home appliances. Therefore, there exists a need for an intermediate hinge assembly which will provide a means of support for the upper door of the refrigerator without unnecessarily adding to the frame or load at the mullion area.